Each reference of scripture (Pill) contains two fundamental doctrines (Ingredients) each. Aside from the doctrine of inspiration and inerrancy of scripture (the Bottle + description as to why), the following are the most attacked, misunderstood, and/or misrepresented biblical doctrines by the world and even in the Church body (1 Pill; 2 ingredients).

1st Pill - Psalms 14:1-3
(1/2) - The Existence of God
(2/2) - The Total Depravity of Man (Romans 3:9-18 & 5:12-16)

2nd Pill - Isaiah 48;16-17
(1/2) - The oneness of God [which is implied here as each one in implication is "LORD" (Deuteronomy 6:4)]
(2/2) - The tri-unity of God (one God in three distinct and co-equal persons: the Father (the "...Lord GOD..."), the Son ("Thus saith the LORD, thy Redeemer, the Holy One of Israel..."), and the Holy Spirit ("...and his spirit...")

3rd Pill - Ephesians 2:8-9
(1/2) - Salvation by Faith Alone
(2/2) - Grace Alone [Sola Gratia... not universally accepted in the Body of Christ; Faith in vs 8: "For by grace are ye saved by faith... it is not of you, it is a gift from God..." (Faith is given by God in the first place). It is a doctrine that isn't needed for the unsaved to believe in order to be saved, but it is the key reason why a sinner is saved. This deserves more explanation (See the bottom of this post)].

It is these three that the world finds most disagreeable because:
1st, no one wants God in order to be accountable for their sins, as well as to bring them low (John 3:18-21).
2nd, no one wants to believe in a very exclusive god which accounts for why we have a plethora of religions [for the theological heretics they either deny the Trinity or misrepresent any of the persons within the godhead in order to suit themselves (Isaiah 43:10 & Romans 1:18-23)]. And ...
3rd, no one wants to be denied of boasting as the given verse bars them of it. If they can gain their own salvation it allows for much boasting as it is given that only the righteous can be with God (Psalms 5:4). Even for one to think they can believe allows for boasting as, if it is true that they can believe, gives them credit.

The 3rd Pill (2/2) is one of the issues most debated within the Church today, because of the notion of free will vs Predestination. Grace (which means Undeserved Kindness) is the quintessential reason why sinners are saved (John 6:37-39, 44, Acts 13:48, & Ephesians 2:8-9). Yet while Grace is the key, it is not necessary for sinners to believe it in order to be saved.